Still working on my 1990300se
replaced o2 sensor(oem).cleared code 17.but cel come back aft 10 or so miles.
now I checked for dc volts at connection under floor mat zero volts! with system connected probing green/black wire with key on nothing now what?

PS not sure which wire I should be testing at.there is one fat green wire coming from sensor and 2 wires that are attached by connector white wire and black with green stripe wire . some one posted to test at black/G wire another forum posted to test fat green wire confused?

This car has to get smogged in march.I know it wont pass with cel on,but I can clear it easily.and it wont come on for 10miles or so I'll take it to a pass or don't pay station hopefully it wont come on during the test.the car runs really good Idles perfect smells ok just that cel comes on!
usually I'm pretty good with trouble shooting skills but have the flu bug I got at work sucks!